Communications devices such as cellular telephones, mobile communication devices, personal digital assistants (PDAs), laptops, and the like are becoming more prevalent as technology advances and makes these devices more powerful and more affordable. These devices are also being constructed with increasing capabilities and can now perform functions that have in the past been performed by dedicated special function communications devices. For instance, a common mobile communications device today may have computing capabilities, the ability to communicate with data networks such as the internet, a display than can render high quality still images and video, audio capabilities that allow the device to play music and video soundtracks, as well as the ability to place and receive traditional mobile telephone calls and text messages.
The expanding capabilities of mobile communications devices have allowed the improvement and enhancement of more traditional technologies. For example, voicemail has traditionally been an audio-only feature that requires a telephone connection to a voicemail server. A user would receive a message waiting notification that a voicemail is available, and the user would then have to dial into a voicemail server to listen to the message. Thanks to technological advances, visual voicemail is available on many mobile communications devices. Visual voicemail presents a visual interface to a user's voicemail box and allows the user to view attributes of voicemail and manipulate voicemail in various ways that were previously not possible. A user may delete or save voicemail through the visual interface without having to place a telephone call to a voicemail server. A user may also be able to see who the voicemail is from, when it was sent or received, and other characteristic of the voicemail without actually placing a telephone call to a voicemail server.
Current visual voicemail services are typically implemented by requesting and establishing a session between a user device and a device in a wireless provider network. When viewed in light of the Open System Interconnection Reference Model (“OSI Model”) communication between a visual voicemail client and a device in a wireless provider network may occur at the application layer using a communications session established at the transport layer, such as a transmission control protocol (TCP) session. For example, a packet data protocol (PDP) context may be activated for a user device by the operating system of the user device. This establishes communications configurations, such as an Internet protocol (IP) address, tunnel identifications, etc., that may be necessary or desired in order to set up a data communications session. PDP contexts may be established on a variety of network devices, including a radio network controller (RNC). Such devices may be configured or capable of maintaining a limited number of PDP contexts, and may be capable of establishing a limited number of PDP context in a set period of time.
Once a PDP context is established, a data communications session, such as TCP session, may be established between an application running on the user device and a network device, such as a voicemail server. Once a session is established, a voicemail server may communicate with a user device at the application layer and transmit voicemail data to a user device. The user device may then transmit an acknowledgement to the voicemail server. Next, the voicemail server will typically set a timer and wait for a period of time, maintaining the data session in case the user device requires any additional activities or data from the voicemail server. If no further activities are requested, the voicemail server will then transmit a request to close the data communications session. However, because the PDP context and the communications session between the user device and the voicemail server occur at different layers of the OSI Model, the user device may determine that the PDP context is no longer needed, for example when a timer expires, and request the PDP context be deactivated even though further communication may be needed between the user device's voicemail client and the voicemail server.
There are several drawbacks to the current methods of providing visual voicemail services. Because the user devices may vary in configuration and design and may not coordinate PDP context use between a voicemail client and an operating system, a user device operating system may close a PDP context before the voicemail client application closes the data communications session with the voicemail server. This may result in the voicemail server maintaining the data communications session unnecessarily while waiting for a timer to timeout, thus wasting server resources. This may also result in the reestablishment of the PDP context in the event that further voicemail activities are needed by the voicemail server or the user device, thus unnecessarily wasting resources on an RNC or other device configured to establish and maintain PDP contexts. It is often less resource intensive to maintain a PDP context than it is to deactivate and reactivate a PDP context, and an RNC or other device configured to establish and maintain PDP contexts may have a limited capability to establish and maintain those contexts. The current methods also require that the voicemail server terminate data communications sessions. Thus, if the user device has closed a PDP context activated for the transfer of voicemail data, the voicemail server or user device will have to reactivate the PDP context just to send a request to the user device close the data communications session. This results in unnecessary utilization of network, mobile device, and server resources.